As documents that describe technologies on wireless systems used in specific areas in mines and the like, there are Patent Document 1 and Patent Document 2.
Patent Document 1 discloses configurations that hierarchical positions (hierarchical levels) according to a predetermined dependency relationship are applied to items of apparatus arranged in a worksite and connected to a network to perform tasks and to receive and/or transmit data and that a correspondence between each item of apparatus and an address structure reflecting the hierarchical position of that item of apparatus is stored to manage communication. At the time of communication, corresponding one of the items of apparatus is selected on the basis of the address structure to establish a communication connection.
On the other hand, Patent Document 2 discloses an information-gathering system that gathers operation information from dump trucks which are traveling in a mine. Via wireless communication equipment, this information-gathering system transmits, at predetermined timings, position information request commands to request transmission of position information of the dump trucks. With respect to each dump truck from which a response has been received at the wireless communication equipment, the information-gathering system gathers operation information of the dump truck, from which the wireless communication equipment has received the response, if the dump truck is able to stay within a communication range of on-board wireless communication equipment until completion of the communication of its own operation information.